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1.
Sci Total Environ ; 792: 148363, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34465051

RESUMO

The alpine meadow in the Qinghai-Tibet Plateau has been seriously degraded due to human activities and climate change in recent decades. Understanding the changes of the soil microbial community in response to the degradation process helps reveal the mechanism underlying the degradation process of alpine meadows. We surveyed and analyzed changes of the vegetation, soil physicochemical properties, and soil microbial community in three degradation levels, namely, non-degradation (ND), moderate degradation (MD), and severe degradation (SD), of the alpine meadows in the northeastern Qinghai-Tibet Plateau. We found that as the level of degradation increased, plant cover, plant density (PD), above-ground biomass (AGB), plant Shannon-Wiener index (PS), soil water content (SWC), soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) decreased significantly, while the soil pH increased from 7.20 to 8.57. Alpine meadow degradation significantly changed the composition of soil bacterial and fungal communities but had no significant impact on the diversity of the microbial communities. Functional predictions indicated that meadow degradation increased the relative abundances of aerobic_chemoheterotrophy, undefined_saprotroph, and plant_pathogen, likely increasing the risk of plant diseases. Redundancy analysis revealed that in ND, the soil microbial community was mainly regulated by PS, PH, PD, SWC, and soil pH. In MD, the soil microbial community was regulated by the soil's available nutrients and SOC. In SD, the soil microbial community was not only regulated by the soil's available nutrients but also influenced by plant characteristics. These results indicate that during alpine meadow degradation, while the changes in the plants and soil environmental factors both affect the composition of the soil microbial community, the influence of soil factors is greater. The soil's available nutrients are the main driving factors regulating the change in the soil microbial community's composition alongside degradation levels.


Assuntos
Microbiota , Solo , Carbono/análise , Pradaria , Humanos , Nutrientes , Microbiologia do Solo , Tibet
2.
J Microbiol Biotechnol ; 31(9): 1218-1230, 2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34261854

RESUMO

Cold-adapted plant growth-promoting bacteria (PGPB) with multiple functions are an important resource for microbial fertilizers with low-temperature application. In this study, culturable cold-adapted PGPB strains with nitrogen fixation and phosphorus solubilization abilities were isolated. They were screened from root and rhizosphere of four dominant grass species in nondegraded alpine grasslands of the Qilian Mountains, China. Their other growth-promoting characteristics, including secretion of indole-3-acetic acid (IAA), production of siderophores and ACC deaminase, and antifungal activity, were further studied by qualitative and quantitative methods. In addition, whether the PGPB strains could still exert plant growth-promoting activity at 4°C was verified. The results showed that 67 isolates could maintain one or more growth-promoting traits at 4°C, and these isolates were defined as cold-adapted PGPB. They were divided into 8 genera by 16S rRNA gene sequencing and phylogenetic analysis, of which Pseudomonas (64.2%) and Serratia (13.4%) were the common dominant genera, and a few specific genera varied among the plant species. A test-tube culture showed that inoculation of Elymus nutans seedlings with cold-adapted PGPB possessing different functional characteristics had a significant growth-promoting effect under controlled low-temperature conditions, including the development of the roots and aboveground parts. Pearson correlation analysis revealed that different growth-promoting characteristics made different contributions to the development of the roots and aboveground parts. These cold-adapted PGPB can be used as excellent strain resources suitable for the near-natural restoration of degraded alpine grasslands or agriculture stock production in cold areas.

3.
Sci Rep ; 11(1): 13552, 2021 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193932

RESUMO

Contrary to the early evidence, which indicated that the mitochondrial architecture in one of the two major annelida clades, Sedentaria, is relatively conserved, a handful of relatively recent studies found evidence that some species exhibit elevated rates of mitochondrial architecture evolution. We sequenced complete mitogenomes belonging to two congeneric shell-boring Spionidae species that cause considerable economic losses in the commercial marine mollusk aquaculture: Polydora brevipalpa and Polydora websteri. The two mitogenomes exhibited very similar architecture. In comparison to other sedentarians, they exhibited some standard features, including all genes encoded on the same strand, uncommon but not unique duplicated trnM gene, as well as a number of unique features. Their comparatively large size (17,673 bp) can be attributed to four non-coding regions larger than 500 bp. We identified an unusually large (putative) overlap of 14 bases between nad2 and cox1 genes in both species. Importantly, the two species exhibited completely rearranged gene orders in comparison to all other available mitogenomes. Along with Serpulidae and Sabellidae, Polydora is the third identified sedentarian lineage that exhibits disproportionally elevated rates of mitogenomic architecture rearrangements. Selection analyses indicate that these three lineages also exhibited relaxed purifying selection pressures.

4.
Front Immunol ; 12: 685896, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34295333

RESUMO

In recent years, more and more studies have shown that early pathogenic bacterial infection in invertebrates can enhance immunity and significantly reduce mortality when reinfected with the same pathogen. There are mechanisms to explain this phenomenon, but they are relatively few. In addition, dose-dependent primary infection is also associated with increased immunity. In the present study, the initial infection dose and mortality of abalone Haliotis diversicolor after reinfection with Vibrio harveyi were recorded, and the mechanism of immune enhancement was investigated by the transcriptomic response of abalone after two successive stimuli with V. harveyi. Priming with different concentrations of pathogen can enhance immunity; however, higher concentration is not always better. Compared with the first exposure, more genes were up-regulated after the second exposure. Among the commonly expressed genes, the immune related genes were significantly or persistently highly expressed after two infections and included pattern recognition receptors as well as immune effectors, such as toll-like receptors, perlucin 4, scavenger receptor class B-like protein, cytochrome P450 1B1-like, glutathione S-transferase 6, lysozyme and so on; in addition, these immune-related genes were mainly distributed in the pathways related to phagocytosis and calcium signaling. Among the specifically expressed genes, compared with the first infection, more genes were involved in the immune, metabolic and digestive pathways after the second infection, which would be more conducive to preventing the invasion of pathogens. This study outlined the mechanism of immune enhancement in abalone after secondary infection at the global molecular level, which is helpful for a comprehensive understanding of the mechanism of immune priming in invertebrates.

5.
Curr Microbiol ; 78(7): 2720-2732, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34023980

RESUMO

The study of the rhizosphere microbial community in salinized soils aids in the elucidation of new and important microbial functional groups, which is of great importance in vegetation restoration and ecological reconstruction of salinized soil. The rhizosphere soil bacterial diversity and community structures of four halophytes, including Kalidium foliatum, Lycium ruthenicum, Karelinia caspia and Phragmites australis, typically distributed in the saline-alkaline land of Southern Xinjiang, China, were studied using an Illumina paired-end sequence platform. The study aims to reveal the alpha diversity, species composition, abundance and the differences of rhizosphere bacteria among the four halophytes, explore their correlation with environmental factors. The results showed that the highest bacterial species diversity was associated with P. communis, followed by K. foliatum, K. caspia, and L. ruthenicum. The species richness was the lowest for L. ruthenicum, while the others showed no significant difference. Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes were the most dominant phyla. And Bacillus and Halomonas were the most common dominant genera. The bacterial communities associated with K. foliatum and K. caspia were similar, while that of L. ruthenicum was significantly different from other halophytes. Soil total nitrogen and total phosphorus, soil organic matter, soil water content, electronic conductivity and pH were identified as the key factors affecting bacterial abundance associated with the assayed halophytes. These results indicate that the four halophytes evaluated in the present study have a similar rhizosphere bacterial community structure due to their being in the same region. However, the bacterial abundance is different among the plant species, and soil properties are the important factors driving the structures of bacterial communities.


Assuntos
Rizosfera , Plantas Tolerantes a Sal , Bactérias/genética , China , Solo , Microbiologia do Solo
6.
Front Immunol ; 12: 659469, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33868307

RESUMO

Gender differences in individual immune responses to external stimuli have been elucidated in many invertebrates. However, it is unclear if gender differences do exist in the Hong Kong oyster Crassostrea hongkongensis, one of the most valuable marine species cultivated along the coast of South China. To clarify this, we stimulated post-spawning adult C. hongkongensis with Vibrio harveyi and lipopolysaccharide (LPS). Gender-based differences in some essential functional parameters of hemocytes were studied via flow cytometry. Obvious gender-, subpopulation-, and immune-specific alterations were found in the hemocyte immune parameters of C. hongkongensis. Three hemocyte subpopulations were identified: granulocytes, semi-granulocytes, and agranulocytes. Granulocytes, the chief phagocytes and major producers of esterase, reactive oxygen species, and nitric oxide, were the main immunocompetent hemocytes. Immune parameter alterations were notable in the accumulation of granulocyte esterase activities, lysosomal masses, nitric oxide levels, and granulocyte numbers in male oysters. These results suggest that post-spawning-phase male oysters possess a more powerful immune response than females. Gender and subpopulation differences in bivalve immune parameters should be considered in the future analysis of immune parameters when studying the impact of pathogenic or environmental factors.


Assuntos
Biomarcadores , Crassostrea/imunologia , Hemócitos/imunologia , Hemócitos/metabolismo , Estresse Fisiológico/imunologia , Animais , Crassostrea/metabolismo , Feminino , Hemócitos/citologia , Histocitoquímica/métodos , Imunofenotipagem/métodos , Masculino , Fagocitose/imunologia , Fatores Sexuais , Estresse Fisiológico/genética
7.
J Hazard Mater ; 415: 125559, 2021 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-33743378

RESUMO

This study aimed to investigate the effect of swine manure composting with microbial inoculation (MI) and without MI (CK) on heavy metal (Cr, Cd, and Pb) fractions, humic substance (HS), and metabolism pathway. The results showed that MI could passivate the heavy metal Cr and reduce the proportion of exchangeable (EXC) fraction of Cd, but it does not affect the EXC fraction of Pb. Compared to CK, HS, humic acid (HA), and fulvic acid (FA) were significantly increased with MI at the maturity stage. The propagation of Proteobacteria (day 4) and Firmicutes (days 12 and 24) was strengthened with MI. Canonical correlation analysis found that HA and Firmicutes were positively correlated with heavy metal (Cr, Cd, and Pb) residual (RES) fraction, and FA was positively correlated with Proteobacteria. Moreover, MI can significantly increase amino acid metabolism and carbohydrate metabolism by day 4, enhance the metabolism of enzyme families and glycan biosynthesis by day 12, and improve membrane transport. Overall, MI could facilitates the increase in HA and FA content and transfer of heavy metal (Cr, Cd, and Pb) fractions, it particularly helps increase the RES fraction.


Assuntos
Compostagem , Metais Pesados , Animais , Substâncias Húmicas/análise , Esterco , Metais Pesados/análise , Solo , Suínos
8.
Environ Pollut ; 276: 116714, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33592436

RESUMO

Antimicrobial resistance genes (ARGs) pose a serious threat to environment and human health. However, few studies address the abundance and distribution of ARGs associated with farmed fish and their aquaculture environment. Here we conducted an analysis of the abundance and distribution of gut and gill ARGs by quantitative PCR techniques associated with the spotted sea bass (Lateolabrax maculatus) as well as the bacterial communities in the surrounding environment (water and sediment). For this purpose, we sampled six aquaculture ponds in Zhuhai, Guangdong Province, the largest spotted sea bass cultivation site in China. Predominant ARGs were floR, sul2, and tetM-01 in the gut and tetQ, sul1, and floR in the gills. The copy numbers of sul1, sul2, and cmlA1-01 were significantly higher in the environment. Moreover, significant differences were found among the microbiota of the gut, gills, and environment. The former was more similar to those of the environmental microbial communities compared with other sources. The fish gut and gill microbiota were predominantly populated by Fusobacteria and Actinobacteria, respectively. In contrast, Proteobacteria were dominant in water and sediment. Correlation analysis showed that Fusobacteria and Actinobacteria positively correlated with floR and tetQ, respectively, indicating that these microbes were potential hosts for ARGs. Our results showed that ARGs in farmed fish showed marked difference with their aquaculture environment, thus providing a valuable reference for identifying deleterious ARGs in aquatic fish.


Assuntos
Bass , Microbiota , Animais , Antibacterianos/farmacologia , Aquicultura , China , Farmacorresistência Bacteriana , Genes Bacterianos , Humanos , Lagoas
9.
Bioresour Technol ; 306: 123167, 2020 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-32192957

RESUMO

This study evaluated enzyme activity, available nitrogen, and bacterial succession during pig manure composting with and without microbial inoculation (ABB and CK, respectively). ABB reached the thermophilic stage 2 days than CK. Cellulose, urease, phosphatase, and sucrase activities were higher in ABB than in CK on days 12-24 of composting, but catalase activity was lesser in ABB than in CK throughout composting. NH4+-N and NO3--N were significantly increased in ABB at the maturity stage. 16S rRNA sequencing revealed Nocardiopsaceae, Bacillaceae, Streptosporangiaceaec, Flavobacteriaceae, and Caldicoprobacteraceae as the dominant bacteria at the family level. Metabolism function analysis revealed that human diseases were reduced and carbohydrate metabolism was increased in ABB. Correlation analysis revealed that urease, sucrose, and phosphatase were significantly correlated with bacteria at the species level, whereas NH4+-N and NO3--N were not significantly correlated. These results indicated that microbial inoculation accelerated the composting process and significantly regulated microbial functions.

10.
J Hazard Mater ; 389: 121834, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-31843407

RESUMO

Environmental problems caused by the large-scale use of chemical pesticides are becoming more and more serious, and the removal of chemical pesticides from the ecological environment by microbial degradation has attracted wide attention. In this study, using enrichment screening with seven chemical pesticides as the sole carbon source, a mixed microbial culture (PCS-1) was obtained from the continuous cropping of strawberry fields. The microbial community composition, degradation ability, and detoxification effect of PCS-1 was determined for the seven pesticides. Inoculation with PCS-1 showed significant degradation of and tolerance to the seven pesticides. Microbial community composition analysis indicated that Pseudomonas, Enterobacter, Aspergillus, and Rhodotorula were the dominant genera for the degradation of the seven pesticides by PCS-1. The concentration of the seven pesticides was 10 mg L-1 in hydroponic and soil culture experiments. The fresh weight, plant height, and root length of PCS-1-inoculated alfalfa (Medicago sativa) significantly increased compared with those of non-PCS-1-inoculated M. sativa. PCS-1 not only effectively degraded the residual content of the seven pesticides in water and soil but also reduced the pesticide residues in the roots, stems, and leaves of M. sativa. This study shows that PCS-1 may be important in environmental remediation involving the seven pesticides.


Assuntos
Poluentes Ambientais/análise , Medicago sativa/efeitos dos fármacos , Microbiota/efeitos dos fármacos , Praguicidas/análise , Microbiologia do Solo , Poluentes do Solo/análise , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Biodegradação Ambiental , Enterobacter/efeitos dos fármacos , Enterobacter/crescimento & desenvolvimento , Poluentes Ambientais/toxicidade , Medicago sativa/crescimento & desenvolvimento , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/toxicidade , Praguicidas/toxicidade , Pseudomonas/efeitos dos fármacos , Pseudomonas/crescimento & desenvolvimento , Rhodotorula/efeitos dos fármacos , Rhodotorula/crescimento & desenvolvimento , Poluentes do Solo/toxicidade
11.
Bioresour Technol ; 289: 121653, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31271913

RESUMO

This study determined the physicochemical changes and bacterial community succession in the pig manure composting process with microbial inoculant. Microbial inoculant could prolong the thermophilic stage by 2 days and increased the germination index (GI). Analysis with 16S rDNA showed that the Chao1 and Shannon indices increased at the thermophilic stage in the treatment (T), while those of the control (C) decreased. Microbial inoculant increased the relative abundance of Flavobacterium and Solibacillus in 4-12 and 12-24 days, respectively. Acinetobacter was reduced at 4-12 days. The key physicochemical factors affecting microbial successions were revealed by canonical correspondence analysis (CCA) and correlation analysis. Linear discriminant analysis (LDA) effect size (LEfse) analysis showed that there were 78 biomarkers, while in piles T and C, there were 35 and 43 biomarkers, respectively. These results indicated the addition of microbial inoculant improved the maturity and fertility, as well as significantly regulating the microbial community structure.


Assuntos
Compostagem , Microbiota , Animais , Bactérias , Esterco , Solo , Suínos , Zea mays
12.
Artigo em Inglês | MEDLINE | ID: mdl-31078702

RESUMO

As one of antimicrobial peptides (AMPs), defensins are involved in invertebrate innate immunity against invading pathogens. In this study, a member of the invertebrate defensins was cloned and characterized from the small abalone Haliotis diversicolor, designated HdDef-2. The HdDef-2 cDNA contained a 201 bp open reading frame encoding 66 amino acids including a signal peptide of 18 amino acids and a mature peptide of 48 amino acids. The mature peptide of HdDef-2 possessed similar features to other AMPs, such as lower molecular mass, net positive charge (+1), and a high hydrophobic residue ratio (45%). In addition, six cysteines in the mature peptide were arranged in the pattern C-X16-C-X3-C-X9-C-X4-C-X1-C and stabilized the α-helix/ß-sheet motif (CSαß) with three disulfide bonds (C1-C4, C2-C5 and C3-C6) in the predicted tertiary structure. Moreover, the similar three-dimensional structure to Anopheles gambiae defensin and a phylogenetic analysis suggest that HdDef-2 may be a new member of the arthropod defensin family. Quantitative real-time PCR analysis revealed that HdDef-2 transcripts were constitutively expressed in the mantle, gill, hepatopancreas, and foot, with the highest level in the hepatopancreas. It was observed that HdDef-2 transcripts were significantly induced in the hepatopancreas after infection by Vibrio harveyi. These results indicate that HdDef-2 may be involved in the immune response against invading pathogenic bacteria, but future work is needed to verify its antimicrobial activity in protein level and elucidate the underlying mechanisms.


Assuntos
Defensinas/genética , Defensinas/imunologia , Gastrópodes/genética , Gastrópodes/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , DNA Complementar/genética , Defensinas/química , Gastrópodes/metabolismo , Expressão Gênica , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/imunologia , Imunidade Inata/genética , Modelos Moleculares , Filogenia , Conformação Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Distribuição Tecidual , Vibrio/patogenicidade
13.
Int J Biol Macromol ; 129: 538-551, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30731165

RESUMO

Hemocyanins (Hc), the main protein components of hemolymph in invertebrates, are not only involved in oxygen transport but also linked to non-specific immune responses. In this study, we used abalone (Haliotis diversicolor) Hc to study the basis of its diversified functions through gene, protein, peptides, and phenoloxidase (PO) activity levels. Three complete hemocyanin gene (HdH) sequences were cloned for the first time. By comparing the copies and location of HdH between abalone and other mollusks, we propose that Hc gene duplication and linkage is likely to be common during the evolution of mollusk respiratory proteins. We further demonstrate that all three genes could be expressed in abalone, with expression varying based on the developmental stages, tissue types, and different pathogen infections. However, HdH1 and HdH2 appear to be synthesized by the same cells by fluorescence in situ hybridization. Furthermore, the PO activity of HdH can be induced by trypsin, urea, and SDS in vitro. Viral infection can stimulate its PO activity in vivo by cleaving the protein into fragments. Consequently, we present a comprehensive study of abalone hemocyanin, providing important evidence for an in-depth understanding of the physiological and immune functions of Hc in mollusks.


Assuntos
Gastrópodes/metabolismo , Gastrópodes/virologia , Hemocianinas/genética , Hemocianinas/metabolismo , Monofenol Mono-Oxigenase/metabolismo , Animais , Gastrópodes/imunologia , Expressão Gênica , Imunidade Inata , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo
14.
Ying Yong Sheng Tai Xue Bao ; 29(11): 3793-3801, 2018 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-30460826

RESUMO

To explore the distribution of bacterial community and its relationship with soil environmental factors in degraded alpine grasslands in the eastern Qilian Mountains, we analyzed the changes of bacterial community structure and diversity across lightly, moderately and severely degraded grasslands by using high-throughput sequencing technology. Redundancy analysis (RDA) was performed to analyze the relationship between soil bacterial communities and soil environmental factors by using CANOCO 4.5 software. The results showed that there were significant differences in soil physicochemical properties among different degraded alpine grasslands. There were 257125 effective sequences, 180826 high-quality sequences and 4790 OTUs. The Chao1 index was lightly degraded grassland > moderately degraded grassland > severely degraded grassland; Shannon index was lightly degraded grassland > severely degraded grassland > moderately degraded grassland. Phylogenetic analysis indicated that the soil bacterial groups of each plot belonged to 33 phyla, with Actinomycetes, Proteobacteria and Firmicutes being the dominant groups in the three grasslands. From analysis of the proportion of soil bacteria in different degraded grassland, we found that the Actinomycetes, Acidobacteria and Proteobacteria increased first and then decreased with the degree of degradation, and the Firmicutes showed an opposite trend. The results of RDA analysis showed that the dominant groups of bacteria were significantly correlated with invertase, cellulase, phosphatas, pH, electronic conductivity, available nitrogen and available potassium. It was concluded that there were significant differences in soil bacterial communities among different degraded alpine grasslands in the eastern Qilian Mountains, and the soil environmental factors were the important factors driving the distribution of soil bacterial communities.


Assuntos
Monitoramento Ambiental , Pradaria , Microbiologia do Solo , Bactérias , China , Filogenia , Solo
15.
Dev Comp Immunol ; 60: 23-32, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26875633

RESUMO

Accumulating data has demonstrated that ferritin plays an important role in host defense responses against infection by pathogens in many organisms. In this study, ultracentrifugation was used to isolate ferritin from abalone, Haliotis diversicolor, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that this ferritin consisted of two subunits (designated as HdFer1 and HdFer2). There are no disulfide bonds between the HdFer1 and HdFer2 subunits; however, these subunits co-assemble to form heteropolymers. A novel ferritin subunit (HdFer2) was cloned from H. diversicolor by 5' and 3' RACE (rapid amplification of cDNA ends) approach. The full-length HdFer2 cDNA sequence consists of 878 bp with an open reading frame of 513 bp that encodes a protein that is 170 amino acids in length. Quantitative real-time PCR analysis revealed that HdFer1 and HdFer2 were transcribed in various tissues, such as the mantle, gill and hepatopancreas, with the highest levels of expression in the hepatopancreas. Following a challenge with the pathogen, Vibrio harveyi, the expression of HdFer1 and HdFer2 were markedly induced at different times. This study has identified a novel ferritin subunit in H. diversicolor which will contribute to further exploration of the role of ferritin in mollusk innate immune defense against invading pathogens.


Assuntos
Ferritinas/metabolismo , Gastrópodes/metabolismo , Vibrio/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Sequência Conservada , Ferritinas/genética , Gastrópodes/imunologia , Gastrópodes/microbiologia , Imunidade Inata , Especificidade de Órgãos , Filogenia , Ativação Transcricional/imunologia
16.
Ying Yong Sheng Tai Xue Bao ; 20(12): 3063-9, 2009 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-20353078

RESUMO

From December 2007 to April 2008, a laboratory experiment was conducted to study the effects of various starvation periods followed by the same refeeding period on the growth, survival, and biochemical composition of different size Ruditapes philippinarum at water temperature 3.0 degrees C-4.2 degrees C, salinity 25-27, and pH 7.90-8.16. No significant differences in the growth characteristics of R. philippinarum at low temperatures were observed among different size groups. The tolerance to starvation increased with increasing size, while the survival rate decreased with increasing starvation period, point-of-no return (PNR50) was not observed during the study period. For the larger size group (7 mm), the body moisture and lipid concentrations generally decreased with increasing starvation period. During starvation, the body protein content increased initially as a result of lipid being utilized for energy, but decreased thereafter when the lipid was depleting. Ash content remained unchanged during the study period, and was not affected by starvation or refeeding.


Assuntos
Bivalves/química , Bivalves/fisiologia , Composição Corporal , Comportamento Alimentar/fisiologia , Inanição , Animais , Bivalves/crescimento & desenvolvimento , Metabolismo Energético/fisiologia , Estações do Ano , Taxa de Sobrevida
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